I would definitely suggest you get any black grill for your AW if you get the spoiler. I had the spoiler installed on delivery and still had the stock grill...looked not too hot. I think because there is some distance between the spoiler and the grill, that as long as it's black (matte or gloss) it will look great! If you want to spend the extra cash and go CF, it's obviously gonna look awesome as well. I have gloss black surround with matte slots. I think it looks just fine.
J